4-MEI is the reason not to avoid a Starbucks latte - 400 calories is.
If you didn't know it, Starbucks has changed their Pumpkin Spice Latte from years past. The surprise was that they have decided to use pumpkin in a drink with pumpkin in the name, the shock is that they are only using pumpkin because of chemophobia about a natural chemical called 4-methylimidazole (4-MEI).
They didn't do it on their own. The activist group which calls itself Center for Science in the Public Interest has ironically been engaged in a war on science since its inception and it senses weakness in groups like Starbucks and Chipotle - if they caved into environmentalist extortion once, they will cave in again. Petitioning the FDA to ban it did no good, because it is harmless, so CSPI and others have been going right to companies with boycotts. They cite the United Nations International Agency for Research on Cancer (IARC) report on 4-MEI, but last week that agency declared that bacon was the same level of carcinogen as cigarettes and Mustard gas so their classifications are taken with a grain of salt (carcinogen!) by the mainstream science and health world.
4-MEI is a natural byproduct of roasting coffee beans and other processes that involve high temperatures and no regulatory body has stated there is a risk from levels in food - naturally occurring or from artificial food coloring. But CSPI and other anti-science groups intentionally conflate hazard with risk - a molecule of anything will cause cancer if a fantastic amount will cause cancer. And 100 percent of your Thanksgiving dinner this month has chemicals known to cause cancer in rats at high enough levels.
It isn't just Starbucks lattes putting you at risk if you are really worried about 4-MEI; it's also in coffee, soy sauce, beer and bread, so CSPI will have something new to scare the public about next week.
If you are not a donor to CSPI or a writer at Mother Jones and are instead interested in an evidence-based assessment of 4-MEI, Dr. Alison Bernstein at Genetic Literacy Project can help.
But the short story is that if you think 4-MEI is the reason not to drink a coffee with calories equivalent to three cans of soda, you need a lesson in nutrition you are unlikely to get at Starbucks.